Remote temperature and/or temperature difference measuring device

ABSTRACT

A remote temperature and/or temperature difference measuring device which includes a measuring circuit having a heat flux sensor for sensing the heat flow from an area on the surface of a body, and a portable housing which supports the sensor and also a device for determining or marking the area of analysis. The measuring circuit includes the heat flux sensor, a memory circuit connected to the heat flux sensor, and a storage input device such as a push button for initiating, at any given moment, the memory circuit&#39;s storage of a reference signal from the heat flux sensor. The measuring circuit also includes a comparator of which one of the inputs receives the output signals from the heat flux sensor, while the other input is connected to the memory circuit providing the reference signal. The comparator thus outputs a signal which corresponds to the difference between the reference signal and a subsequently received heat flux sensor output signal. An indicator device is also included, and it is connected to the output of the comparator for producing a signal which corresponds to the above mentioned differences. The device is especially suited for measuring the temperature on the surface of a human or animal body.

The present invention relates to a temperature and/or temperaturedifference measuring device.

To make such measurements, it is known to use heat flux sensors whichpick up the infrared radiation emitted by an area of the surface of abody, so as to deduce therefrom the temperature of the area and/ortemperature differences.

However, these known devices perform poorly when measuring very smalltemperature differences and they are not easy to use.

The particular aim of the present invention is to remedy thesedisadvantages and provide a remote temperature and/or temperaturedifference measuring device which comprises a measuring circuitcomprising a sensor of the heat flux emitted by an area of the surfaceof a body and a housing carrying this measuring circuit.

The remote temperature and/or temperature difference measuring devicecomprises, according to the present invention, a measuring circuitcomprising a sensor of the heat flux emitted by an area of the surfaceof a body and a portable housing carrying the aforesaid sensor as wellas means for marking the explored area.

According to one subject of the invention, the measuring circuitcomprises a memory circuit connected to the heat sensor, a storage inputunit such as a push button for effecting, at any chosen instant, thestorage in this memory circuit of the signal coming from the aforesaidheat sensor, which then constitutes a reference signal, a comparator,one of the inputs of which receives the output signals from the heatsensor and the other input of which is connected to the said memorycircuit providing a reference signal, this comparator providing at itsoutput a signal corresponding to the difference between the saidreference signal and the signal coming from the heat sensor, as well assignaling means connected to the output of the comparator and providinga signal corresponding to the aforesaid difference.

According to the invention, the said marker means preferably comprisemeans enabling the said housing to be stationed in a specified positionwith respect to the surface of the body and may furthermore beadjustable.

In a preferred variant, the said marker means comprise at least twolight emitters whose light beams produce on the surface of the bodylight spots which, only when the housing is in the aforesaid specifiedposition, are in specified positions with respect to one another.

According to the invention, the light emitters can advantageously bearranged on either side of the volume sighted or explored by the heatsensor and emitting light beams inclined with respect to the axis ofthis volume.

According to the invention, the said light emitters are preferablyadjustable and are rotationally connected so as to vary the angle oftheir axis with respect to the axis of the explored or sighted volume.

According to the invention, at least one of the aforesaid tracespreferably coincides with the surface of the said body explored by theheat sensor.

The device according to the invention can furthermore comprise meanssuch that the explored or sighted volume is a cylinder.

In a preferred embodiment, the said housing has an aperture behind whichis stationed a reflecting means, the heat sensor being stationed infront of this reflecting means, this reflecting means being such thatthe explored or sighted volume is cylindrical.

The said housing can also comprise a lateral grip for grasping, to thebase of which is connected the aforesaid push button.

The present invention will be better understood on studying a remotetemperature and/or temperature difference measuring device described byway of non-limiting example and illustrated by the drawing in which:

FIG. 1 represents a section in elevation of a temperature measuringdevice according to the present invention;

FIG. 2 shows an exterior view of the temperature measuring devicerepresented in FIG. 1;

FIG. 3 represents a view of the left side of the temperature measuringdevice represented in FIG. 1;

FIG. 4 represents a view corresponding to FIG. 3, of the temperaturemeasuring device, in another position of adjustment;

FIG. 5 represents the block diagram of the aforesaid temperaturemeasuring device.

Referring to FIGS. 1 to 4, it can be seen that the remote measuringdevice represented, labeled in a general manner with the reference 1,comprises, for example, a plastic portable housing 2 which has acylindrical or square cross sectional portion 3, one of the ends ofwhich has an aperture 4 and which has, remote from this aperture, atransverse wall 5 delimiting a front chamber 6.

On the side of the wall 5, the housing 2 furthermore has a chamber 7which has in one direction two parallel walls 8 and in the oppositedirection a wall 9 and an inclined wall 10 through which the chamber 7is prolonged inside a grip 11.

The walls 8 and the wall 9 prolong the portion 3. The grip 11 isinclined substantially at 45° with respect to the axis of the portion 3and on the side of the latter and extends perpendicular to the wall 10.Opposite the wall 5, the chamber 7 is closed by a wall 12 curved in thedirection of the walls 8.

The temperature measuring device 1 comprises a measuring circuit labeledin a general manner with the reference 13, which is carried by thehousing 2.

This measuring circuit 13 comprises a heat flux sensor 14 which ismounted in the chamber 6 of the housing 2, remote from a parabolicmirror 15 fixed against the wall 5. The heat flux sensor 14 is fixedalong the axis of the chamber 6 for example by radial lugs which are notshown. The reflecting mirror 15 is such that the face of the sensor 14pointing towards the mirror 15 receives, through convergence, the heatflux seen, in a sighting cylinder 16, through the aperture 4 and aroundthe sensor 14.

The temperature measuring device 1 furthermore comprises marker means,labeled in a general manner by the reference 17, serving in thepositioning of the housing 2.

These marker means 17 comprises two light emitters constituted bylight-emitting diodes 18 and 19 which are stationed on either side ofthe cylindrical portion 9 of the housing 2 and which are carried by twoU-shaped supports 20 and 21 articulated horizontally on the housing 2 byparallel shafts 22 and 23 which are perpendicular to the axis of thecylindrical portion 3 of the housing 2. These two supports 20 and 21 arerotationally connected by toothed crown segments 24 and 25 and can berotationally immobilized by virtue of a screw 26 which passes through acurved oblong hole 27 made in one of the wings of the support 21.

Thus, the light-emitting diodes 18 and 19 emit conical light beams 28and 29 whose axes cut the axis of the parabolic mirror 15 at the samepoint.

In the example described, when the measuring device 1 is suitablystationed with respect to a surface 30, that is to say when the axis ofits cylindrical portion 3, which is coincident with the axis of theparabolic mirror 15 which corresponds to the axis of the sightingcylinder 16, is stationed perpendicularly at the proper distance fromthe surface 30, the two light traces of the light beams 28 and 29 on thesurface 30 must be substantially coincident, these two superimposedtraces covering and coinciding with the area of the surface 30 seen bythe sensor 14 through the sighting cylinder 16.

If the measuring device 1 is not at the proper distance or i.e. isinclined with respect to the surface 30, the traces are not in thedesired position with respect to one another.

As FIG. 3 shows, the diameter of the sighting cylinder 16 can be variedby stationing in the aperture 4 of the chamber 6 a diameter-reducingring 31 which could be replaced by an adjustable diaphragm.

In order optionally to adapt the marker means 17 to this new sightingvolume, it suffices to modify the angular adjustment of the supports 21in order to modify the angle made by the beams 28 and 29 emitted by thelight-emitting diodes 18 and 19.

Referring now to FIG. 5, it can be seen that the measuring circuit 13comprises an amplifier 32 which receives the signals provided by theheat sensor 14, a comparator 33, one of the inputs of which is connectedto the output of the amplifier 32 and the output of which is connectedto a signaling means 34.

The measuring circuit 13 also comprises a memory circuit 35 the input ofwhich is connected to the output of the amplifier 32 and the output ofwhich is connected to the other input of the comparator 33. This memorycircuit 35 serves to store at a given instant the output signal from theamplifier 32, this operation being carried out by virtue of a storagecommand input unit consisting in the example of a push button 36provided at the base of the grip 11, on the side of the housing 2.

In the example represented in FIG. 1, the signaling means 34 consist onthe one hand of a series of luminous diodes 37 stationed on the wall 12of the housing 2 and a warning sounder or speaker 38 stationed in thechamber 7 of this housing.

The amplifier 32, the comparator 33 and the memory circuit 35, as wellas the ancillary components which are not shown, are for example carriedby a printed circuit 39 mounted in the chamber 7 of the housing 2 andsupplied via an electrical load 40 passing through the end of the grip11.

To use the measuring device 1 described above, the following proceduremay be undertaken.

Firstly, the diameter of the aperture 4 is adjusted to the desireddiameter in order to fix a diameter particular to the sighting cylinder16. The inclination of the light-emitting diodes 18 and 19 is adjusted,thus determining a particular measuring distance with respect to thesurface 30 to be explored.

The measuring device 1 is held in the hand by the grip 11.

The measuring device 1 is stationed at the proper distance and at theproper angular position with respect to the surface 30, this positionbeing attained, in the example, when the two light spots obtained viathe light beams from the light-emitting diodes 18 and 19 are coincidentand substantially circular.

A pressure is exerted on the switch 36 so as to effect the storage inthe memory circuit 35 of the output signal from the amplifier 32corresponding to the measurement of the heat flux emitted by thecorresponding area of the surface 30 towards the heat sensor 14.

The measuring device 1 is moved so as to bring it, as before, into theproper position with respect to another area of the surface 30.

The comparator 33 then compares the output signal from the amplifier 32,which corresponds to the heat flux emitted by this other area towardsthe heat sensor 14, with the signal stored in the memory circuit 35.

The result of this difference is transmitted to the signaling means 34,which in the example represented in FIG. 1 comprises the loudspeaker 38producing a corresponding specified sound level and/or modulation and acorresponding specified number of diodes 37 being lit up.

The operator can then ascertain whether the two areas compared are atthe same temperature or are at different temperatures and can qualifythis difference.

Naturally, if the signal stored in the memory circuit 35 corresponds toa particular known temperature, the operator can not only detecttemperature differences between several areas but also the temperatureof each of the areas, provided for example by the luminous diodes 37.

The operator can, at any instant which he chooses, modify the referencesignal stored in the memory circuit 35. To do this, he need only actuatethe push button 36.

Owing to the fact that the sighting or exploration volume 16 iscylindrical and by virtue of the optical marker means 17, the measuringdevice 1 makes it possible to qualify very small temperaturedifferences, at least down to a tenth of a degree, in particular fordistances of between 0.10 m and 1 m, it being possible for the diameterof the sighting cylinder to be between 0.015 m and 0.04 m.

The measuring device described above can advantageously be used tomeasure temperature differences between various areas on the surface ofa human or animal body, so as to determine or confirm a medicaldiagnosis. Indeed, its structure is designed so that it is very easilymanipulated and so that it enables temperature differences to bemeasured by taking a reference area which it can change when it wishes,in particular so as to carry out comparisons of temperature in zoneswhich are associated from a medical point of view.

The present invention is not limited to the example described above. Inparticular, the luminous marker diodes could produce different traces indifferent positions of adjustment on the surface to be explored andcould be replaced by other marker means, especially optical, inparticular by an emitter stationed just in front of the sensor andemitting a light ray along the axis of the sighting cylinder towards thesurface to be explored. The circuit for measuring heat flux could bedifferent especially as regards its arrangements in the portable housingand its signaling means which could comprise for example graphicalprinting means possibly outside the housing or other means. The pushbutton or any command input unit could be outside the housing.

We claim:
 1. Device for measuring temperature and/or a temperaturedifference of a surface, comprising:a housing; a measuring circuitsupported by said housing, said measuring circuit including a heat fluxsensor with output, a memory circuit in communication with the output ofsaid heat flux sensor, an input unit adapted to activate said memorycircuit so as to memorize an output signal from the output of said heatflux sensor while the heat flux sensor senses a first explored surfacearea, and the memorized output signal constituting a reference signal, acomparator having a first input connected to said memory circuit and asecond input connected to the output of said heat flux sensor, and saidcomparator having an output for delivering a signal corresponding to anydifference between the reference signal and a subsequent output signalof said heat flux sensor, and a signaling means connected with theoutput of said comparator for providing a signal corresponding to anydifference between the reference signal and said subsequent outputsignal; and marking means for designating an area on said surface forsensing by said heat flux sensor, and said marking means being supportedby said housing.
 2. Device according to claim 1, wherein said markingmeans includes means for positioning said housing at a specifiedposition with respect to the surface of a body.
 3. Device according toclaim 1, wherein said marking means includes an adjustment assembly forvarying in size the designated area.
 4. Device according to claim 1,wherein said marking means includes at least two light emitters (18, 19)which are adapted to produce light beams that produce on the surface ofa body light spots which, only when the housing (2) is in a specifiedposition, are in specified positions with respect to one another. 5.Device according to claim 4 wherein said light emitters (18, 19) arearranged on opposing sides of wall surfaces of said housing and areoriented so as to emit light beams at an incline which converge at aconvergence location on the surface of the body.
 6. Device according toclaim 5, wherein said light emitters (18, 19) are adjustably supportedon said housing and are rotationally connected to said housing such thatthe angle of incline of the light beams and a distance between the heatflux sensor and the convergence location are adjustable.
 7. Deviceaccording to claim 4 wherein said housing includes a front chamber inwhich said heat flux sensor is positioned, and said front chamber havingan aperture formed therein and an aperture ring for adjusting theaperture size.
 8. Device according to claim 7, wherein said lightemitters are dimensioned and arranged so as to form coinciding lightspots which have a diameter in common with that of said aperture whensaid housing is at a specified position.
 9. Device according to claim 8,further comprising a reflecting means, said reflecting means beingpositioned such that the heat sensor (14) is stationed between thereflecting means (16), and the explored surface.
 10. Device according toclaim 1, wherein said housing (2) comprises a lateral grip (11) forgrasping, and said input unit includes a push button (36).
 11. A deviceaccording to claim 2, wherein said marking means (17) are adjustable.12. Device as recited in claim 1 wherein said marking means isdimensioned and arranged for assisting an operator of said device indetermining whether said heat flux sensor, while sensing at a secondexplored surface area, is at a similar distance and angular orientationwith respect to the second explored surface area as was said heat fluxsensor when sensing said first explored surface area.
 13. A device formeasuring temperature and/or a temperature difference comprising:ahousing; a measuring circuit supported by said housing, said measuringcircuit including a heat flux sensor with output, a memory circuit incommunication with the output of said heat flux sensor, an input unitadapted to activate said memory circuit so as to memorize an outputsignal from the output of said heat flux sensor as a reference signal, acomparator having a first input connected to said memory circuit and asecond input connected to the output of said heat flux sensor, and saidcomparator having an output for delivering a signal corresponding to anydifference between the reference signal and a subsequent output signalof said heat flux sensor, and a signaling means connected with theoutput of said comparator for providing a signal designating anydifference between the reference signal and the subsequent output signalof said heat flux sensor; and a marking assembly supported by saidhousing, said marking assembly including a first light emitter supportedon a first support, which first support is adjustably secured to saidhousing, a second light emitter supported on a second support, whichsecond support is adjustably secured to said housing and in engagementwith said first support so as to coordinate movement of said first andsecond light emitter, and an immobilizer member for fixing in place saidfirst and second light emitters such that light beams produced by saidemitters converge at a location removed from said housing.
 14. A deviceas recited in claim 13 further comprising a mirror (15) positioned suchthat said heat flux sensor is positioned between the mirror and asurface area being measured.
 15. A device as recited in claim 13 whereinsaid housing includes a handle grip and said input unit includes a pushbutton or switch supported by said handle grip.
 16. A device as recitedin claim 13 wherein said signaling means includes a speaker.
 17. Adevice as recited in claim 13 wherein said housing includes an extendedportion with aperture formed therein, said extended portion defining achamber within which is supported said heat flux sensor.
 18. A device asrecited in claim 17 further comprising an aperture ring for varyingaperture size of the aperture of said extended portion.
 19. A device asrecited in claim 18 further comprising a parabolic reflector mirrorpositioned at an end of said chamber and said reflector mirror having acentral axis which intersects said heat flux sensor and coincides with acentral axis of the aperture.
 20. A device as recited in claim 17wherein said marking assembly is supported by said extended portion. 21.Device as recited in claim 1 wherein said signaling means includesluminous diodes.
 22. A device as recited in claim 13 wherein saidsignaling means includes luminous diodes.